This Week... A grotesque serial killer (Michael Massee) strikes, but his unusual motivation leads Olivia (Anna Torv) to reconsider her feelings. Meanwhile, Peter (Joshua Jackson) encounters September (Michael Cerveris) once more and learns a shocking truth...

Observing Fringe... As Fringe returns from a month-long hiatus, newly-widowed women are being attacked in their homes by a disfigured intruder. Former perfumer Anson Carr (Massee) is exposing his victims to pheromones - almost a love potion - but the placating effect quickly dissipates and he's forced to take lethal action...

Advertisement - Continue Reading Below

What's more, each of the widow's husbands has been found with their bodies completely drained of moisture. With his bizarre experiments and horrific appearance, Carr's enough of a creepy-crawly to make a fitting villain.

But what really makes him a compelling nemesis for the Fringe team is his complexity. Carr's motivations are ultimately good, if a little warped, and despite his terrible actions, he even shows some mercy - letting one couple go free because they have a young child.

That said, it's a shame that the villain-of-the-week plot comes to such a perfunctory end - our heroes track down Massee's villain, he's captured and taken away in handcuffs - end of. Such an intriguing character deserved a stronger exit.

All this talk of love and romance has the Fringe leads considering their own relationships. Olivia's old personality continues to flood back, but at a cost - her memories of this timeline are fading...

Apparently rejected by Peter, she begs Walter (John Noble) to save what's left of her crumbling mind, but, in the end, decides that an Olivia with Peter is a "better" Agent Dunham, giving everything up for the man she loves.

The decision leads to a touching scene between Olivia and Nina. This writer hasn't really bought into the pair's new mother / daughter relationship this season, but Anna Torv and Blair Brown are unquestionably brilliant in this final scene.

Credit also to the Fringe writers and to Seth Gabel for ensuring that Lincoln Lee is a sympathetic third wheel - even though we want Peter and Olivia to be together, you can't help feeling a little sorry for Gabel's bespectacled FBI agent.

Like Diana Sutter (Ona Grauer) says, there's a difference between loving someone and being in love with them - and that's the difference between how Olivia thinks of Lincoln and how she feels about Peter.

Speaking of Peter...there's more to September's visit last episode than meets the eye - his disappearance was the result of an uber-quick rescue by the other Observers, but before he was spirited away, September left something in Peter's retina…

Pausing in his endeavour to make himself as miserable as possible, Peter discovers that the disc left behind is etched with an address, which leads him to September's base of operations.

His investigation eventually uncovers a beacon, which summons September - who tells Peter what the audience already knew (or at least strongly suspected): "You have been home all along."

The notion that Peter survived being erased from existence because his friends and family care about him too darn much ("I believe you call it…love!" stutters September) is a little twee, but by this point, the viewer is so happy - and relieved - to have the story arc resolved that it doesn't really matter.

Peter and Olivia's final embrace is a wonderfully happy moment, but what's next? Will the others follow suit in remembering Peter or will Olivia have to help guide them?

Regardless, with seven episodes remaining, now was the right time to resolve Peter's quest and, as usual, Fringe did it with a great deal of style and aplomb.

• This week's Fringe glyphs spell out the word Q U I L L - As in the writing instrument? We'll be honest, the significance of this is lost on us...